The present invention relates generally to vehicle seat assemblies and in particular to a seat assembly having an inflatable air cushion mounted to the seat frame.
In recent years automobile manufacturers have directed increasing attention to providing improved side impact protection for vehicle occupants. One method of doing so is to provide an inflatable side impact air cushion mounted to either the vehicle seat or the door adjacent to the vehicle seat.
To provide an air cushion module in a vehicle seat having a folded air cushion and a gas generator, two difficulties must be overcome. The first is that of packaging the air cushion module within the seat. When an air cushion module is added to a seat, care must be taken to ensure that acceptable foam thicknesses are maintained for seating comfort. However, the foam thickness cannot simply be increased to cover the added air cushion module. Increasing the foam thickness adds to the size and weight of the seat assembly, both of which are counterproductive as auto makers seek to build smaller and more fuel efficient automobiles.
Accordingly, it is one object of the present invention to provide an air cushion module in a seat and to package the air cushion module in the seat assembly without significantly increasing the size and the weight of the seat.
The seat of the present invention overcomes the packaging difficulties by installing the air cushion module within the hollow interior of a seat frame component. By placing the module within the seat frame as opposed to mounting the module to the seat frame exterior, there is little, if any, added structure which must be covered with foam. An additional advantage flows from mounting the module in the seat frame. In order to place the module in a frame having a closed cross-sectional shape, an opening must be formed in the frame by removing a portion of the frame wall. By removing a portion of the frame material, the frame weight is reduced. This weight reduction would not occur if the air cushion module is simply mounted to the exterior of the seat frame.
The second difficulty in providing a seat air cushion relates to the provision of a path for back pressure release gas from the gas generator. The gas generator, when provided in a seat assembly, is typically surrounded by the seat foam cushion. There is a concern that the release of back pressure gas into the foam can excessively heat the foam, resulting in foam damage. This difficulty with the back pressure release is not present in front impact air cushions that are mounted within an instrument panel or steering wheel since they are not surrounded by foam. Likewise, side impact air cushions mounted in a vehicle door are not surrounded by foam either. Accordingly, it is another object of the present invention to provide a back pressure release passage which avoids the release of hot gases directly into the foam.
The seat assembly of the present invention overcomes this difficulty by releasing the back pressure gas into the hollow interior of the seat frame. The seat frame provides a large accumulator for released gases, allowing the gases to cool before they ultimately dissipate through various apertures in the seat frame into the surrounding foam. As a result, there is no damage to the seat cushion foam caused by the release of hot gases directly into the foam.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description and the appended claims when taken in connection with the accompanying drawings.